NOPSEMA briefing and MODU mooring systems in cyclonic conditions - - PowerPoint PPT Presentation

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NOPSEMA briefing

and MODU mooring systems in cyclonic conditions

Kerry Gordon

Manager – Assessment & Inspection 10 Sept 2015

Selected topical issues

• Triennial independent review of NOPSEMA

– Stakeholder engagement continues to be a focus

• Legislative change

– Amended Wells Regulations commence 1 Jan 2016

• NOPSEMA focused topic inspection program

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Focus topics 2015

Maintenance management

• management of deferral of work
• equipment strategies - inspection and monitoring
• structural integrity - inspection and monitoring
• safety-critical equipment meeting performance standards.

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Focus topics 2015

Contractor management

• Contractor agreements and performance governance by the
• perator in relation to:

– how the operator of a diving project effectively ensures diving contractors are complying with their DSMS/DPP – third party contractors & equipment management – asset integrity monitoring programs conducted by third parties.

• Contractor selection and competency
• Operator and contractor interface management e.g. SIMOPS.

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Focus topics 2015

Blowout source control contingency planning

• Currently the degree of contingency planning for a well

blowout (relief well, cap and contain etc) varies between

• titleholders. NOPSEMA will inspect titleholders

arrangements for compliance with the legislation.

– Note: new well regulation RMAR Part 5, Reg. 5.09(k) now specifically addresses the matter.

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Focus topics 2015

Position keeping systems

• Stability management including Ballast & Bilge Systems.
• Dynamic positioning systems
• Pre-lay mooring design
• Inspection testing and maintenance including software

updates

• Integrity of safety critical elements
• Competence (operators and maintainers of position keeping

systems).

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MODU mooring systems in cyclonic conditions

Background

• The Atwood Osprey experienced a mooring failure

during cyclone Olwyn and was blown some three nautical miles off location in the vicinity of subsea and surface infrastructure and environmentally sensitive shorelines

• Investigations have been conducted by NOPSEMA

and Atwood who have both committed to sharing lessons learned from this incident with industry.

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Sequence of events - Cyclone Olwyn

• 9 March – Commence well suspension in preparation for rig evacuation
• 10-11 March – Osprey completes well suspension, power- down and

evacuation

• 12 March – TC Olwyn strikes Atwood Osprey
• 12-13 March – AHTSV reports rig off location ~3nm

13-man team arrives on board to take the rig in tow by the AHTSV and holds station; team departs rig

• 14 March - Commence ROV operations to assess seabed and condition of

infrastructure.

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Regulatory perspective

Four known Incidents of MODU loss of position due to Cyclone activity

• Mar 2004 – MODU dragged anchors

Cat-3

• Dec 2008 – MODU dragged anchors

Cat -2

• Feb 2011 – MODU dragged anchors

Cat -3

• Mar 2015 – MODU snapped anchor wire

Cat -3

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Regulatory perspective

Six documented instances where MODUs have failed to down- man in the face of impending cyclones.

• Semi-Sub MODU 2004
• Jack-Up MODU

2006

• Semi-Sub MODU 2007
• Semi-Sub MODU 2009
• Semi-Sub MODU 2011
• Semi-Sub MODU 2015

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Regulatory perspective continued

Inconsistency in safety case design and performance standards utilised in mooring design and analysis.

• “50 year return period”
• 1 case
• “API RP 2SK using 20 year return period”
• 2 cases
• “API RP 2SK using 10 year return period”
• 1 case
• “specification to ABS rules and MODU code”
• 1 case
• completely silent on design and performance

standards for mooring systems.

• 3 cases

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Investigation overview

• Hind-cast computer modelling
• ROV survey of the seabed
• Review of the mooring system design and its

component parts

• Inspection of critical components
• Visual inspection, metallurgical analysis and

destruction testing of the mooring lines

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Investigation overview continued

• Design including pre-laid systems
• Assurance, installation and managing change
• Inspection and maintenance.

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Findings - Mooring design

• Return period (20,50,100 year RP environmental

conditions)

• Component positioning
• Lack of detailed risk assessment at the mooring

design stage involving all parties

• Deficiencies in the assurance processes at the

interfaces between the responsible parties.

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Mooring installation - Interface

Combination of rig and pre-laid mooring components

• Pre lay mooring installation procedures
• Drag anchor pull test tensions
• Management of change.

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Operations, inspection and maintenance

• Records of inspection history
• Frequency of inspections
• Competency assurance system for mooring

equipment/rope inspectors

• Lack of performance standards and the

necessary associated assurance tasks for the mooring system – ongoing availability and reliability of the SCE

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Recovery preparedness

Opportunities for improvement

• Procedures for managing mooring line tensions

for survival conditions/MODU cyclone evacuation

• MODU real time position indication - GPS
• Mooring line tension/weather recording and

UPS

• MODU recovery – preparedness for towing

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Key learnings - Mooring failure

• Reliability of the mooring system under foreseeable

cyclone conditions

• Assurance of mooring design, installation and

critical component materials – quality control

• The interface: SCE - inspection, maintenance, MoC

and operations procedures

• Recovery preparedness and. response

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Regulatory approach and expectations

MODU mooring workshop

Provided an opportunity for industry and NOPSEMA to collectively examine better ways to manage this significant risk.

• Provide information about the incident and lessons learned
• Communicate regulatory requirements and perspective
• Discuss opportunities for improvement

– identify any actions on which immediate consensus can be reached – identify areas for which there is consensus in direction but require more work to define detail.

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Workshop inputs

• NOPSEMA and Atwood investigation findings
• Information paper provided for context
• Consideration of existing standards and practices

from elsewhere

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Regulatory expectations

To strengthen requirements with a view to improving the situation:

• Achieve consensus on what is best practice in relation to

each of these issues;

• Determine current industry knowledge and approach with

respect to mooring design criteria;

• Assess and manage the risks arising from these issues with

respect to the impending cyclone season and longer term.

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Regulatory expectations

Safety case considerations:

• rig operators - mooring systems are safety critical

Current considerations:

• understand the design basis and integrity of current

hardware

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Next steps

NOPSEMA will issue regulatory guidance:

• to address key issues identified and recognized in the

workshop and in the information paper;

• to raise awareness and prompt a review of arrangements in

place for the immediately forthcoming cyclone season; and

• to provide guidance on key interface points between

titleholders and operators which should be addressed in the rig safety case

Methodology for topics requiring further work

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Thankyou